Conventional pumps have many parts and usually include o-rings or other seals. This sharply drives up their cost of manufacture. Improvements could therefore be made in providing a pump that is simpler in design and less costly than conventional offerings.
An internal combustion engine has been proposed by which a set of pistons and cylinders, disposed in parallel to a central axis but radially displaced therefrom, provide power to a central shaft by means of a cam drive. See United States Patent Application Publication No. US 2008/0105222 A1 to Kubes et al. But this arrangement heretofore has not been applied to situations in which a central drive shaft supplies rotational power instead of receiving it, and in which the pumping of a fluid is the desired work.